Researchers wanted to know whether vomit could facilitate the spread of norovirus, a highly contagious stomach ailment notorious for turning unlucky cruise ships into ground zeroes for diarrhea epidemics. But first, they needed a way to reproduce the physical action of vomiting -- so they built a "vomiting device" to puke on command in the lab.
Here it is in action:
Science is glorious.
By using the device to approximate the spray of human vomit, the researchers found the first direct evidence that norovirus can be spread by way of the technicolor yawn. Their findings were published Wednesday in the journal PLOS ONE.
"When one person vomits, the aerosolized virus particles can get into another person's mouth and, if swallowed, can lead to infection," study co-author Lee-Ann Jaykus of North Carolina State University said in a statement. "But those airborne particles could also land on nearby surfaces like tables and door handles, causing environmental contamination. And norovirus can hang around for weeks, so anyone that touches that table and then puts their hand to their mouth could be at risk for infection."
In other words, you don't have to have direct exposure to vomit contaminated with norovirus in order to get sick. The physical act of vomiting helps the virus proliferate by leaving behind particles much less conspicuous than a puddle of sick.
In addition to a viral soup the likes of which would be found in a sick person's puke, the researchers used vanilla pudding to simulate the viscosity of vomit. They determined that 800 milliliters of vomit was a good upper threshold, while anything lower than 50 milliliter of liquid would count as a "dry heave". They also determined that coughs were common after the act of vomiting, so they were sure to simulate a few sharp exhalations with their device during the experiment.
Ultimately, only around .02 percent of the viral particles ended up airborne, with the rest staying put inside the viscous fake vomit. But that small percentage still amounts to thousands of viral particles -- ones that could end up on hands, toilets and door knobs, just to name the most likely of surfaces.
And those errant particles are more than enough to cause infection.
In further experiments, Jaykus and her colleagues will determine just how long these viral particles can survive on different surfaces -- and how far a spew of vomit is able to project them.